SCS Drow City

I've tried many a time to defeat the improved Drow City, but I always end up getting overwhelmed. I do have the tweak installed that allows multiple summons (As I like the whole large scale battle idea, I dont abuse it with multiple Planetars etc :P)

Does anyone have any tips and tricks for it? I've taken a new approach last time that seemed to work quite well, which was to place Traps throughout the city so that when they actually turn hostile they instantly take some damage. I've done the same with some of the buildings (put traps at entrances and lured certain groups inside)